How to convert an integer to a string portably?

Question

I was looking for a way to convert an integer to a string in a portable manner (portable among at least Windows & Linux and x86 and x86_64) and I though itoa(X)

Answer 1

If you aren't doing this terribly often, how about a runtime library routine that writes a few numbers to memory, analyzes the results and stores an encoding type? From then on you just switch on your "encoding type" to select which conversion routine to use.